1. Field of the Invention
The present invention is related to a method for controlling a dew prevention heater.
2. Description of the Prior Art
For the purpose of raising the user's convenience and spatial efficiency, a door apparatus (hereinafter, called a French door apparatus), in which two doors are disposed on the left and right sides of a single compartment and designed to be opened and closed at the center of the compartment, has been developed. This French door apparatus is favorable to a refrigerator with large volume.
FIG. 1 is a perspective view of a conventional refrigerator with a French door apparatus.
Referring to FIG. 1, refrigerator 100 with a French door apparatus has two doors 110L and 110R attached to a single compartment. The side edges of doors 110L and 110R are rotatably supported by respective upper and lower hinges 102U and 102L secured to each corner of the front side of the compartment. Two handles 104L and 104R are secured to the other end portions of doors 110L and 110R.
FIG. 2 is an enlarged cross sectional view of the contact portion of two doors in a refrigerator as shown in FIG. 1.
Referring to FIG. 2, a narrow gap A is provided between doors 110L and 110R so that doors 110L and 110R may be effortlessly opened or closed. Furthermore, a partition member 114 is rotatably secured to the inner wall 112R of either door 110R in order to prevent air from circulating through the narrow gap A. The partition member 114 is rotatably supported by hinge axis 116.
In the afore-mentioned construction, partition member 114 unfolds as shown in FIG. 2 when doors 110L and 110R are closed, whereas when doors 110L and 110R are opened, partition member 114 rotates together with door 110R and folds into a receiving member 118 arranged in the vicinity of hinge axis 116.
By the way, the interior and exterior surfaces of partition member 114 are continuously in contacts with relatively cool and warm air in the interior and exterior portions, respectively of the compartment. Accordingly, unwanted dew forms on the exterior surface of partition member 114. To prevent this formation of unwanted dew, a heater 120 is conventionally provided in partition member 114.
A more detailed explanation of the French door apparatus and the mounting structure of the heater will be omitted because it is disclosed in many patent publications, including Japanese Patent Laid-Open Publication No. 113268 (May 14, 1991).
FIGS. 3(A) to (C) are schematic diagrams showing conventional driving systems of a dew formation prevention heater(s) for a refrigerator.
In FIGS. 3(A) to (C), reference numeral 1 denotes a relay switch; 2 denotes a compressor; 3 denotes a dew formation prevention heater (hereinafter, called an F/heater) for a freezing compartment; 4 denotes a dew formation prevention heater (hereinafter, called an R/heater) for a refrigerating compartment; and, AC denotes a commercial A.C. power supply source.
According to FIG. 3A, the F/heater 3 is always activated and R/heater 4 is activated together with compressor 2 in FIG. 3b both F/heater 3 and R/heater 4 are activated together with compressor 2; in FIG. 3C the F/heater 3 solely provided is activated together with compressor 2.
However, the conventional driving systems have some problems in that excessive electric power is consumed by the heater(s). Therefore, the refrigerating ability deteriorates because the activation of the heater(s) is controlled without consideration of the outer temperature of the refrigerator and the indoor temperature of each compartment. In addition, the conventional driving systems of the heater(s) have a problem in that the formation of dew is not effectively prevented.